Project Background/Rationale. Parkinson's disease (PD) is the second most common neurodegenerative disease, affecting over one million Americans. The cardinal clinical manifestations of PD are motoric, which limit functional mobility leading to difficulty working, caring for family members, managing a household, and overall decreased independence and quality of life (QOL). A wealth of growing data indicates tremendous benefits of exercise for patients with PD. Not only have exercise programs been shown to improve motor function and reduce the risk of falls, but also improve overall QOL and possibly the very course of the disease pathology. However, programs that involve supervision in the home of people with PD are expensive to roll out widely, and programs that involve people with PD traveling to a central site not only result in non-compliance over time because of difficulty getting to the site, but als rule out the involvement of a large number of people with PD who simply live too far from larger centers where such programs are typically established. Project Objectives. The overall goal of the proposed research is to evaluate the effectiveness of a novel home-based approach to providing the known benefits of a safe exercise program to people with PD. A successful home-based exercise program that included real-time, but remote supervision from trained personnel could not only avoid the above-mentioned limitations, but also potentially maintain, at relatively low cost, long-term adherence to such exercise programs and thus sustained benefits. Specifically, we will determine whether a one-year in-home exercise program, centered around remote, real-time instruction and supervision using a smartphone technology (Mobile-PAL), will reduce the rate of falls, and improve strength, physical function and QOL, in patients with PD. Project Methods. We propose to conduct a randomized controlled trial of an exercise program delivered via the Mobile-PAL system, evaluating effects on fall rate, physical functioning, and QOL. Community-dwelling people with mild to moderate PD will be randomized either to a group that receives remote exercise instruction and supervision in real-time for 12 months or a group that receives health education information by smartphone at regular intervals over the year. The exercise group will participate in a modified version of exercise programs previously shown to be effective, which includes stretching, strengthening, and balance exercises. The modifications made are to adapt the program to that which can be done safely by the patient in their own home without in-person supervision. Remote supervision will be provided at regular intervals via a real-time video chat between the patient and the physical therapist. This allows the therapist to walk through the exercises with the patient as he performs them in his home. In addition, outcome assessments will be conducted remotely via a real-time video chat between the patient and a trained research assistant under the supervision of the physical therapist.